Just changed the clutch on my V6.
The top starter motor bolt really is a pig to undo, but it was made much easier by locating a spanner bent 90 degrees (as mentioned earlier) over the bolt head and easing the vertical part of the spanner 'clockwise' using a small pry-bar, pivoting on the the bellhousing... remember the bolt head is facing away ;-)
This solution worked a treat and after a couple of turns the bolt could be unscrewed by hand (small hands!).
Hopefully this will save some of you guys a couple of hours of swearing and cursing, and saves having to remove any down pipes.
I also did not need to remove the sub-frame.... the box does come out eventually :-)